Thread checking apparatus



Aug. 31, 1948. w. MANNERBRINK Erm.

mam cancun@ Arrlmuus 3 Shoots-Sheet 2 Filed Aug. 9. 1944 U8- 31,1948. w.'MANNERBR|NK Erm. u 2,448,106

l raam cnncxme Arxgmvrus Filed Aug. 9, 19444 ashun-sneu a Patented Aug. l3l, i948 443.108 THREAD -cnacxmo arrsas'rus [van Waldemarl Mannerbrlnk andv Nils Johan Ludvig Sandstrm, Goteborg, Sweden, assignors to. SKF Industries, Inc., Philadelphia, Pa.,I a corporation of Delaware v application August s, 1944, serial Na. 548,516

In Sweden August 12, 1943 9 Claims. (01.33-199) -The presentl invention relates to a thread checking apparatus and has for its purpose to provide `an instrument forrapid and easy check of'v the diameters of threaded parts. paratus is specially suitable for checking the fit The apof threaded Darts.

. One embodiment Voi thev invention is illustrated on the `accompanying drawings, inlwhich Fig. 1 shows a vertical section through the yapparatus and Fig. 2 is a horizontal section through the same. Fig. 3'shows a side view of the apparatus. Fig. 4 shows on a larger- Scale means ior positioning the arms of the apparatus during operation," Fig. 5 shows also'on 'a'- larger scale," the .location of the measuring points when checking external-threads. Fig. 6 is a, fragmentary plan view of two lof theelements of the apparatus'ln the relative positions which they occupy in assembly. Fig. 7 is a side elevational view of the sub-assembly shown in Fig. 6,-"ancl Fig. 8 is a diagrammatic plan view illustrating a structural and functional detail `of the apparatus Af shaft 3' isv mounted on ball bearings 2 in a frame I. On the shaft l is rigidly mountedI a rigidv arm 4 which thus can oscillate with the shaft. Another oscillatory arm i is' mounted on the shaft 3 by means of a pair of ball bearings.

8'- and thusv is capable of oscillationv 'not only relativeto the shaft 3 but also relative the arm- 4.l In'other-wfrds. both arms willl oscillate about the. axis of the .,halft 3, the arm 4 with the'shaft and the arm l independently of the shaft, so that the arms may assume various angles with respect to each other, each in its individual plane of'oscillation perpendicular to the shaft axis.

As shown in Fig. 2, the arm 4 is forked at the end which is attached to the shaft 3 and the han bearing meuntror the, arm s 1s between the forks of the arm 4. The relationship of the two ai-"ms may be better understood by reference to .v Fig. 6,-and 'I of the drawingswhich show the arms in the relative positions assumed in the assem- Blidably mounted `on a bar 'I screwed to the arm 4. lislaA4 counterwelght 4 and another slidable counterweight s is mounted on a bar I 0 screwed to the arm 5. By the aid of .these two slidable weights I and l. the whole arm mechanism4 can lie-balanced in a. manner whichv makesv it easily movable around the bearings. The device is therefore more convenient than others having slides or the like. ,i y .The arm 4 is rigid, but the arm S is in two psrtaconnectedtoesch other by means of two leaf springs II. vThrough this arrangement the outer ypartl! of the arm can make a parallel sidewise movement' relative to the inner part of the arm. that is to say, parallel to the ascii-- latory axis of the arm 5. This movement is also relative to the rigid arm 4. Slidably mounted in a groove I3 in the arm 411s adjustable vertical arm I4, which has a thread contact point I5. `Ini a similar groove I6 in the outer part I2 of the arm t is a. similarly slidably adjustable vertical arm,

iiprovided'with thread contact point I8. 'I'he-I points Il and It are thus movable relative to each other. The points are conical with an apex angle'equal to the thread angle. They there''l fore correspond to the theoretical thread profile vand thus permit an exactchecking of the ilt of the work piece. 0n an arm IS perpendicular to andy supported by the arm 4 is a dial indicator gage 20, the measuring point 2i of which abuts against a surface on the movable outer part I2 of the arm 5. The arm IS is integral with or rigidly attached to the arm 4. The relative movement and the relative positions of the part I2 andthe rigid arm l4, i. e. between the thread contact points I5 and I8,'can thus be-read on v the indicator dial 20. The arm' I9 is prolonged in the opposite directionand has 'a screw 33, which can be adjusted in the arm and is providedwith a scale 22, by the aid vof which the position of the screw can be read. Coacting with the scale 22 is a relativelyfixed pin 4I! (see Figs.

l and 2), said pin, with the scale, aifording a means for indicating th'e angular position of the -screw 33 and hence the axial or longitudinal adjustment thereof in the arm I9. As described below.A the screw constitutes .a medium for ad justing the relative height of, or the difference in height between, the points I5 and Il, as indi.

cated at 25 in Fig. 1, and the scale 22, usually graduated in tenths of millimeters, will indicate such difference.

- 'I'he screw carries at its lower end two discs 23 which loosely embrace one end of an arm 24 4 perpendicular to the movable arm 5, said arm 24 being fastened4 to the part I2 of the arm 5. 'I'he arms 4 and 5 are therefore coupled to one another and consequently oscillate together aroundl the. axis of the shaft 3, but their relative positionl can be adjusted bymeans of the-screw 33 andl the scale 22. Because ofthe play in the coupling which permits of a certain motion bclatweenV the arms, it is always possible for the thread contact points to enter the thread. As illustrated in Fig. ll their mutual position is adjusted in such.

manner that the vertical, distance 25 between I2 of the arm can be moved sideways with respect to the arm 4.

At the end of the frame is fastened a plate 21 having a notch 2l (Fig. 4). The notch 2l has for its purpose to position the handle 20 when the same is moved sideways. The reason for this is that since the measuring points are mounted on the ends of oscillable arms, they thus move along arcs or circles.- Consequently the result of the checking operation is influenced to some extent, although" indeed very inconsiderably, by the position on the arcs, at which the contact points happen to be located when the reading is made. The notch ensures that, when checking a. series of similar work pieces, the arms will always assume the same positions and consequently, this inconvenience is avoided. The plate 21 is provided with a slot 4I which permits it to be slid along guides 4t on the frame I and to be locked in desired position of adjustment by means of a screw 42. The plate 21 can also be applied on the other side of the handle 2l in corresponding guides 43u, when necessary, which will be the case when the apparatus is used for checking external threads and the thread Vcontact points are applied as shown in Fig. 5 v

The work rest 2l is attached to the upper surface of the frame by screws (not shown). The rest is substantially circular in shape (although this is immaterial) and is provided with a slot lla through which the arms I4 and I1 project.

The work rest is provided with an adjustable pin 3| which serves to position the work piece, and when the apparatus has been adjusted for the thread Vdiameter to be checked the work piece will assume of its own accord, when resting against the pin 30 and the point Il, such a position that the points Il and Il will be on one of its diameters. In order to cause the workpiece to assume a position in contact with the lpin 2l, the work rest' is inclined, and the inclination of the work rest can be altered by adjusting the length of an adjustable ieg OI on the frame. To this latter end the frame is formed with a pair of feet- 44 having curved surfaces a which rest upon the underlying surface. At its other end the frame is supported by the leg lI which, as

stated above, is adjustable in the frame so as Ato adjust the height of that end of the frame and. thereby, the inclination of the frame as a whole. As shown in Figs. 2 and 3, the leg Il passes through and is releasably clamped in a split collar IIa on the frame.

The pin Il is of circular cross section and is adjustable longitudinally of a dovetail slot a in the work rest 2l at right angles to a line between the points Il and Il. As stated above, it is positioned ln the slot so that when it is engaged with the threaded surface of the work piece the points 'Il and Il will be located on a diameter of the thread. This is illustrated in Fig. 8 oi' the drawings, wherein the work piece l2 is shown in the normal relationship to the pin Il and points Ii and II. If the pin is located to the left of the radial line normal to the diametrical line deilned by the points I5 ner. The weight of the arms is counter balanced by the aid of the weights l and l, and the inclination of the work rest is fixed. Thereupon' the vertical distance between the arms (i. e. distance between the measuring points) relative to one another is adjusted by means of the screw 3l and the scale 22. The distance between the measuring points is adjusted so that with thev work piece In position, as described above, theA vtwo points Il and Il will normally lie sumciently far apart to reach to the bottom of the thread, but will be sufficiently close together in against the fixed point Il.

The apparatus is used in the following man# `be made to exert a biasing the normal positions to permit retraction of the point I8 to an extent permitting Linsertion and subsequent release of the work piece from between the points. As stated, the pin l0 is positioned sothat the measuring points will contact with the threads of a master ring on a diameter and the indicator dial is adjusted to zero position. The apparatus is now ready for use. When placing the workpiece 32 on the rest, the measuring point Ii, when checking internal threads, is moved towards the point I6, which means that the handle 2l shall be moved to the right until it engages the notch 2l. This has thedouble effect of removing the point Il to a retracted position free from interference with the workpiece, so that the latter may be placed in the apparatus, and of establishing the points in predetermined angular positions with respect to the axis oi' shaft 2, in which positions the points are to operate in the checking operation. The work piece is turned until the fixed measuring point enters the thread.- Then the handle 2i is released and the movable point, by

action of the spring Il hereinafter described. automatically enters the proper thread and the reading is made while the work piece, is rctated ywhereupon the handle 20 is again moved to the right, the work piece is removed, and another work piece is inserted. The measuring points can freely follow the thread, while the work piece is ,being rotated, which makes it possible to check'the roundness of the thread.

With reference to Fig. ,2, it willl be noted that a lea! spring mounted in the arm I, extends outwardly between the springs II and termi-- nates in a recess I2a in the member I2. The spring 4i is supported in a cylindrical member 4l which is mounted for rotational adjustment in a vertical socket la in the arm i, such adjustment being effected in the present instance by means of a screw 41 threaded into a depending lug 5b of the arm l and having a flange 4l which extends into a notch lla in a member 4I ilxed to the lower end of the member By adjustment oi' the screw I1 the spring 4I may pressure on the member I2 tending to displace that member and the point Il which it carries either toward or away from the arm I and the relatively fixed point Il. Where the gauge is to be used on 'an internal thread the said resilient bias will be away from the'point Il; and when an external thread is to be checked the bias will be toward the point I5. This device permits the springs II to function solely for the support and guidance of the member I2 and provides an adjustable means for obtaining a regulated pressure of the points against the thread of the work piece whether internal or external'.

Having thus described our invention, we

claim and desire to secure by Letters Patent the following:

1. Thread diameter checking apparatus comaua-ice w yprising a iramehaving a work-receiving table for supporting a workpiece; a pair of thread' contact points, a pivotal support for each of said points, means for mounting said-supports in the frame lfor oscillation about a common axis in parallel planes substantially normal to the plane of the work-receiving table. said points being oppositely directed on a line substantially parallel with said commQn axis, and means movably connecting one oi" said supports and itsl associatedv point -i'or permitting movement o! said point toward and from the other. said connection guid- -ing said point -in said movement in a path substantially parallel to the said common axis.

2. Thread diameter checking apparatus com.

prising a frame having a work-receiving table for 'supporting a workpiece, a pair oi' thread contact points, a support for each of said points pivotally mounted in the frame on a 'common' axis substantially' parallel to the plane of said work-receiving table, said points being oppositely directed on a" line substantially -parallel with said common axis, and a movable guiding and table, a pair of oppositely directed thread contact points mounted one on each of said arms and' each directed transversely of its arm on a line substantially parallel to the plane of said table, a movable guiding and connecting means between one of vsaid contact points and its support i'or permitting movement of said point toward and from the other of said points in a path substantially parallel to said common axis, said last mentioned means guiding said point during such'movement, and means for' so moving said point.`

4. Thread diameter checking apparatus comprising a frame havinga work-receiving table for supporting a workpiece, an axle rotatably mounted in the said frame substantially parallel with the plane of the said work-receiving table, an arm xed to the' said axle and .another arm mounted for oscillation on and about the said ciated`arm for permitting guided movement -ot said point in the said transverse direction and with respect to said arm.

v(i. Thread diameter checking apparatus com- I prising Ia frame having a work-receiving table for supporting a workpiece, a pair of arms, means for pivotally mounting said arms in the frame for free and independent oscillation about a common axis substantially parallel with the plane ofthe work-receiving table, said arms being positioned on the same side of said common axis, and slidable yweights connected to'said arms and positloned on that side o! said common axis opposite that on lwhich said arms are positioned, said weights counterbalan cing the weight of the arms, a pair of oppositely directed thread contact points carried one on each oi' said arms and directed transversely thereto, and a movable guiding and connecting means between one oi said.

arms and its associated point for permitting movement of said point on its arm in the said transverse direction, said last mentioned means guiding said point for movement in said transverse direction. A

7. Thread diameter checking apparatus comprising a frame having a work-receiving table for supporting a workpiece, a pair of arms, means for `pivotally mounting said arms in the frame for axle, a'pair of oppositely directed thread contact points mounted one on each of said arms l and directed transversely thereto, andaI movable guiding andconnecting means between one oi said arms and its associated point for permitting movement of said point on its arm in the saidtran'sverse direction, said last mentioned means guiding said point for movement in said transverse direction.

5. Thread diameter checking apparatus ccmprising a frame having a work-receiving table for supporting a workpiece, a pair of arms, means for pivotally mounting said arms in the frame for free and independent oscillation about a common axis in parallel planes substantially normal to the plane of the work-receiving table, a pair of oppositely directed thread contact points carried one on each of said arms and directed transversely thereto, and resilient guiding and connecting means between one of said points and its assofree and independent oscillation about a common axis substantially parallel with th-e plane of the work-receiving table, adjustable coupling members connecting the arms for adjusting the relative angular position of the arms about said common axis, a pair of oppositely directed thread contact points carried one on each of said arms and directed transversely thereto, and a movable guiding and connecting means between one of said arms and its associated point for permitting movement of said point in the saidi transverse direction, said last mentioned means guiding said point for movement in said transverse direction. 8. Thread diameter checking apparatus comprising a frame having a work-receiving table for supporting a workpiece, a pair of arms, means for pivotally mounting said arms in the frame for free and independent oscillation about a common Aaxis substantially parallel with the plane of the work-receiving table, adjustable coupling members connecting the armsfor adjusting the approximate relative angular position of the arms about said common axis, there being a limited slackness between the coupling members whereby there may be limited'free relative movement between the arms, a pair of oppositely directed thread contact points carried one on each of said and directed transversely thereto, and a movable guiding and connecting means between one of said arms and its associated point for permitting movement of said point in the said transverse direction, said last mentioned means guiding said point for movement in said transverse dil rection.

9. Thread -diameter checking apparatus comprising a frame having a work-receiving table for supporting a workpiece, a pair of arms, means for pivotally mounting said arms in the frame for free and independent oscillation about a common axis substantially parallel with the plane of the work-receiving table, a pair of oppositely directed thread contact points mounted one on each of said arms and directed transversely thereto, a movable guiding and connecting means between one of said arms and its associated point for permitting movement of said point on its arm in the means guiding said point during its movement in said transverse direction, a handle for eectingsaid movement, adjustable coupling means for connecting the arms in predetermined relative angular positions with respect to the said axis, and means on the frame for engaging the asiq handle to determine the positionof the arms relative to the trame during application oi' the .workpiece to the work-receiving table.

IVAN WALDEMAR MANNERBRINK Nus JOHAN LUDVTG sANDsTRu The following references file oi' this patent:

announces man UNITED STATES PATENTS Number Bauer Oct. 22,

are vof record in the 

